Place 2 tblspn oil into a large non-stick frying pan over
medium-high and heat until hot. Add
mushrooms and cook, stirring, for 4-5 minutes or until pan juices have
evaporated.Remove from heat, drain
excess liquid and set aside 10 minutes. Combine mushrooms, beef mince, onion,
salt and pepper, Worcestershire sauce and egg in a large mixing bowl.Mix well using your hands. Form mixture into
eight patties, place onto a tray, cover with plastic
wrap and refrigerate for 20 minutes. Heat a large non-stick frying pan on
medium-high heat.Cook patties for 4-5
minutes on each side or until cooked to your liking. Grill hamburger buns. Top
bun bases with shredded lettuce, sliced tomato and two patties. Drizzle with
barbecue sauce to serve.